Flow control of particles in fluidized processing



Feb. 5, 1952 J. BEAM 2,584,378

FLOW CONTROL OF PARTICLES IN FLUIDIZED PROCESSING Filed De 25, 1949 1'1' L fgezzerafo; r

Patented Feb. 5, 1952 UNITED STATES rr wr omce ration of Delawareaptlitationiaecemba- 23, 19.49, seen No. 13435":

1 This invention relates to means for effecting the 01 a; the flow ortransfer of "particles 50m one esmactmg zone to another in fluidizediii-Gees rig op'e'rati'en's, and more i)atticularly to the utilizationo'f fiet-like streams of a gas er taper; to control the rate 01withdrawal and transferof 'sub'divided particles from each of thecont/acting zones in a manner which eliminates the need of expensivetyne of' slide valves or similar inechanic'alfcontifol means;

In the usual fiui'diz'ed'unit, such'asthe fluidized catalyst plants thatare "u'j'sed in the e oleum c'hem'lcal processing fields, the subdiv edcataly'st particles are contacted at least we "s'epa' fate Cohfllld261185, a leai3l3l(il'1 "Qh-llibel and a i'eactivation chamber. Theparti'cle's 'be'ing continueusly passed from one chamber to another toprovide a continuous 'convers'ionproce'ss. The

rate of withdrawal of particles and transfer beit'ween zones, has ingeneral been controlled by the useof'slide valves placed an the-particlewith drawal conduits or standp'ipes from each cffthe contacting zones.The particles being withdrawn in a substantially fluidized column fromthe respective contacting beds within each cf the conversion contactingchambers. The Withdrawal conduits are usually relatively large, thus theslide valves which are placed therein "are necessarily a large type ofvalve requiring rather expensive hydraulic or mechanical type of powerto efiect their automatic adjustment during the operation of theprocessing unit. Also, slide gate type cf valves, when used in fluidizedparticle processing, are subject to considerable Wear and erosion fromthe continuous stream of particles such that it is necessary to spendcon- .siderable on upkeep and maintenance.

Itis, therefore, a principal object of the present It is a furtherobject of the invention to utilize transversely positioned jet streamsat the lower end of each particle withdrawal conduit from each zone, ina manner to regulate the flew ,of particles from each zone and the rateof par- 'ticle transfer to the other-of thecontacting zones.

.11; is a still further object of the present invention to arrange andutilize the jet streams in a manner whereby instrumentation connectingwith suitably lccated pressure and temperature 'sensitive instruments-may be" utilized in combination with the fiet streams toeffectcontinuous 9 Claims. (Cl. "196- 52) automatic contr o l "'o'fthig'flnidieed processing Briefly, the present "simplified method ofcon;-

trolling the withdrawal and transfer of particles between contactingzones of a fluidized conver- "sion unit, wherein the particles arecontacted by difierentreactant streams in the different ccntactingzones, 'coninri ses the iniiarovementof con- 'tinuously withdrawingbarticles iron; each of the contacting zones in a relatively dense phasefluidized 06111115111, inaimaining at least two jet streams "of a fluidmediuin below eacn oi the particle withdrawal colunrm's directingone jetre ly; intQF Qh i e e. 09 1 1 in a manner hindering the withdrawalofgparticles, directing. hefetMreifihe ie xstr jm e h cas awa sf mih i eel 'mn ner transferring particles to the other ofth'e zones, andcontinuously proper oping stream flow between the jet -streams ateachwithdrawal column r i l s iw i r h t e ect t e re at on a control of thetransferof particles between con- Zones: 1 l v In a preferred operationand -arrangement, the transversely positionedjet streams, at eachwithdrawal sta'ndpipe and descending column of particles, are fed with asimilar or a common fluidmedium and r'neans stich as a singletwo wayvalve is utilized to proportion the flow of the 'streams between the twojets, su'chthat a constantgaseous orvaporous flow is divided between thetwo streain's and the 'valve adjustment to increase one stream decreasesthe flow through e he a "wnrer s lr. v, o

A preferred arrangement also utilizes an offcenter yane atjthe lower endcream of the ithdrawal conduits, so thatlthe latter is meted orcontrolled by the jet stream dirqted'upwardly in, to the descendingcolumnof A, particles and the P ur ar at n fe t by b th the et streamsto provide :a ($10853 control of the withdrawal of the particles. "Theoff-center vane in each case Qpcrates :FO permit flow of particles onlywhen 'thepressure below the vane is less than the pressure thereabove,and thus the a f er'ernentioned substa 11y verticalhorizontal transverseJe t e m ps ind lo a h o thew'ithdrawa'l columns oi particles, Inlay beoperated -effectiyely in combination with the vane to regulate pressureth erebelow and in turn reg- 111m, nd ce re hefl e e ri e bei with?drawn em we z ne and transferred t th other.

r as mast anti-e ement e w present simplified -.method of ape-ration toell-mihate the expensive type of slide valve, hydraulic operatingsystem, and instrumentation that is necessary in the operation of suchvalves. The present control system may also be used to advantage inconnection with contacting zones which are maintained at substantiallylow levels, where there are no great standpipe heights utilized forbuilding up dense phase pressure within the withdrawal column ofparticles and permitting differential pressure in the zones. In otherwords, the transverse jet streams at each of the withdrawal columns ofparticles may be regulated within a relatively wide range of pressure,such that difierent pressures may be maintained within each of thecontacting zones. Further, in a preferred embodiment of the unit, whichutilizes two way valving means to proportion the stream flow to each ofthe jet streams, automatic controls may be readily adapted thereto,whereby to provide a continuously operating plant and to effect theproduction of. desired product streams from each of the conversion zonesand to closely control the withdrawaland rate of transfer of particlesbetween the zones.

The accompanying drawing and the following description thereof willserve to more fully describe theoperation of the present invention,while additional advantages will be apparent in connection with thedescription relating to the drawing. In the drawing, Figure l is adiagrammatic illustration of a conversion system embodying the inventionand Figure 2 is a fragmentary detailed view, partially. in section, of aportion of said system.

Referring now to the drawing, there is indicated a vertically disposedconfined reaction chamber I and a similar vertically disposed chamber 2,indicated as-a regenerator. For purposes of simplification, thesubsequent description of the drawing will bedirected toward thefluidized catalytic cracking of an oil stream, wherein a gas-oilcontacts a suitable cracking catalyst in a reaction zone, and carbonizedcatalyst particles are continuously contacted with air or other oxygenstream in a regeneration zone to efiect the burning and removal ofcarbonaceous contaminating material and to effect the heating of theparticles to' a desired temperature for supplying heat to the reactionzone. It is, however, not intended to limit the present operation toonly the fluidized catalytic cracking of an oil stream, for obviously,the process and method of operation may be readily used in connectionwith any conversion operations which are adapted to the fluidizedcontacting of subdivided particles. A relatively dense-phase fluidizedbed of particles is maintained in the lower portion of the reactor i,having an upper extremity indicated by the brokenline 3, with thefluidization maintained by gases and vapors introduced to the lower endof thereactor I by way of riser line 4'- and the perforated grid ordistributing plate 5, which is in turn suitable to evenly distribute thegaseous stream across the entire cross-sectional area of the reactionzone.

Inthe present instance, hot reactivated catalyst particles are indicatedas being transferred to the lower end of the reaction zone by way of theconduit 4 and by means of a steam stream which is indicated as beingintroduced through conduit 6 and control valve 1 to the riser line 4.The gas-oil or'other hydrocarbon stream to be converted, is introducedto the riser line 4 by way of line 8 and control valve 9, and theresulting vaporous s'treamji's distributed into the reaction zone in anupflow' along with the sub- '4 divided catalyst particles. Thehydrocarbon conversion product stream leaves the upper end of thereactor I by way of a particle removal and recovery apparatus In and theoutlet line H having control valve l2. The recovery unit I0 is indicatedas being of a centrifugal type of separator suitable to recover andcollect entrained solid particles and return them to the dense phase bed3 by way of a suitable dip leg I3.

Contaminated catalyst particles are continuously withdrawn from the bed3 within the reaction zone] by way of a suitable withdrawal well l4 andconduit l5 which connects with a suitable enlarged stripping chamber l6.Preferably steam or'other relatively inert fluid medium suitable toremove and strip occluded hydrocarbon vapors from the surface of thecatalyst particles, is introduced by way of line I! and control valve l8at the lower end of the stripping chamber itself. Resulting strippedvaporous materials and the stripping medium pass outwardly from the topof the stripping zone, through conduit [9, to the upper portion of thereaction zone I, while substantially stripped particles are continuouslyallowed to pass downwardly in a relatively compact or dense phase columnof particles within the conduit or standpipe 29.

The standpipe 28 has a swinging vane member 2| positioned within thelower portion thereof and just above the conduit 22 which connects in amanner to transfer particles to the regeneration zone 2. Positioneddirectly below the conduit or standpipe 20 are two jet-like nozzles 23and 24, the latter directed upwardly into the standpipe 20 and againstthe vane 21, in a manner to hinder the downward flow of particles pastthe off center vane, while the jet 23 is positioned transverse theretoand provides an eductor efiectsuch that particles which are passedonwardly through the standpipe 2e and past the vane 2| are jetted intothe conduit-i2- and subsequently into the regenerating zone In thepresent embodiment, air is indicated as being charged to conduit 25 andthrough the two way va1ve26 to both the conduits 22 and 21, with the airpassing through conduit 22 being jetted through the nozzle 23 and theair passingby way of conduit 21 being jetted through the vertical nozzle24.

In accordance with the preferred operation of the present embodiment ofthe invention, a substantially constant quantity of air is intro ducedby way of line 25 such that adjustment of the two way valve 26 effectsthe proportion ing of the air between the two jet nozzles 23 and 24.Thus, where it is desired to decrease the amount of particles withdrawnby way of the standpipe 20 and passing to the regenerat ing zone 2, thevalve 26 is adjusted such that a quantity 'of gas passing upwardlythrough jet 24 and against the lower side of the vane 2i is sufiicientto partially close the vane and slow down the withdrawal of particles,while simultaneously, the quantity of air decreases through jet nozzle23 and the resulting eductor effect into transfer line 22 is decreased.In the reverse situation, where it is desired to have an increased flowof particles from the reaction zone to the regenerating zone, the valve2% is adjusted to increase the jet flow to nozzle 23 and decrease theflow to nozzle 24 and against the lower side of the vane 2|, so that alarger quantity of particles passes downwardly from the lower end of'the standpipe and .intdthe transfer conduit 22. Proper adjustment of thearse-ave valve-2e maintains the desirediproportlon" of the,

reaction zone.

aid in the response to the upwardly flowing; jet stream fromthe-nozzleit and pressure changes in the lower end of the conduit. In addition;the vane prevents an entire reversal of flow of particles upwardly-intothe reactor by way of the stripper and withdrawal well M, for withalarge quantity of fiuidizing medium jetting upwardly from nozzle 24 thevane 2 l closes and substantially'prevents the gaseous medium passing'on upwardly;- through the descending columnof particles. r

j Automatic control or the -'proportioning= valve 26 may be effectedthrough suitable level con-- troliinstrumentation-as indicated inthedrawing: A- pressure sensitive control point within the upper portionof the reactor at 28. and a control point 29 at the lower end of thereactor, and suitable transmittal lines 30 and '3I respeotively; whichconnect witha controller 32, provideforthe continuous indication ofthe'fluidi ed' bed level within the lower portionof the Thecontaminated. catalyst particles, being withdrawnzirom the reactionzone; are'continuous'ly'passed by way of the riser'conduit 22 into thelower end of the regenerating chamber 2 and continuously distributedthrough a grid or suitable perforated plate 34 intov a relatively densephase fluidized bed of particles maintained within thev lower portion ofthe regenerator and indicated by the broken line 35. 'l-he air streamutilized to. transfer the particles to the regener ator efiects theburning and oxidation of contaminated'carbonaceous' matter on theparticles, such that the latter may be continuously withdrawn from theregenerator substantially free of coke and carbon deposit. Particlesbeing withdrawn are continuously passed through the withdrawal well 35and the conduit or standpipe 31, while resulting combustion gases orflue gases pass from the upper end of the regencrating zone by way of aparticle separator 38 and outlet conduit 39- having control valve 48.The particle separator 38 is advantageous in the recovery of entrainedcatalyst particles, preventing their passage with the fiue'gas to thestack, returning them to the contact bed within the lower part of theregenerator byway of a suitable dip leg 4|.

" The reactivated particles being withdrawn through standpipe 31, passin a continuous de scending column to the transfer conduit 4. As inconnection with the withdrawal of particles from the reaction zone; anofi-center swinging type of vane 42 is maintained within the lower endof the stand pipe 3 7, and transversely positioned nozzles or jets 423and 44 are maintained at the lower end of the standpipe. The steamstream which is introduced by way of the conduit 15 and throughproportioning valve 1, is split between the two jet nozzles, with aportion of the steam passingby way of the conduit 45 and jet is directly'up into the standpi-pe 31 and against the lower side of the'swingi-ngvane 42,

;.- ablczcontroller 45 through. a control line All.

while;thc-rcmainingrpontiongcfzthe steam passes through.-thesubstantially horizontal et nozzle 44 in;ajet eductor-typeoiyoperation to transfer pm'ticles:into the-conduit '4. Also, inaccordance with the preferred type of" operation, asubstantiallyoonstant volumeor quantity of steam is introduced through; line 6, suchthat adjustment; of: the proportioning: valve '5 effects the transferof, a greater orl'esser quantity of the particles to: the reaction zonefromv the standpipe 31 and" regenerationzone- 2. As previously describedin: connection with the. other withdrawal, zone, an adjustment of thevalve to increase flow through vertical jet 43 and decrease flow:through eductor jet. providesa decrease in the rate of: withdrawal ofparticles past the swinging vane; 42, and a decrease in the volumeoffsteam; passing through jet 43 with an increase through jet M"efiectsan increase in the rate' of withdrawal. of particlesagnd in therate of trans.- fertothereaction zone;

In; an automatic type-pf operation, the proportioningvalve I maybeof themotor or dia phragm controlled type and, connect with a suit- Thepresent embodiment indicates the controller Mi as connecting with; atemperature sensitive instrument iB; through a control line 49, suchthat the valve 7 is adjusted inv relation to the variations intemperature. within the bed 3, as noted by the. temperature sensitive.instrument 48. In a hydrocarbon. cracking operation, such as indicatedand described here, the. temperature with in the reactionzone; maybecontrolled by the rate of; flowv of; hot. catalyst particles from theregeneration zone, so that where additional tema nerature is indicatedasbeing required in the reaction zone, the controller 46 may operate toadjust the proportioning'valve 1 to. in turn allow a faster rate ofwithdrawal through line 37 and intothe transfer line 4.. VAutomaticinstrumentation is also indicated in the drawing in connection,with themaintaining of pressures. within the. reaction and regeneratetion. zones; with pressure sensitive instruments 50' and. 5|. inthercaetion and regeneration zones respectively, connecting to adifferential pressure controller 52' by means of suitable connect inglines 53; and 5.4;.- The, controller 52 in turn connectsby way or 1ine55to valve 46, which may be: motor or diaphragm. operated to regulate therate Oi disch r e OI flue ases from the regeneration zone and control.the diiierential pressure etween the two contacting zon s.-

It m y be p n th tin connection. with the aseous streams belua-introduced the dificrsnt standpiess and into the transf r lines ateach. of. the withdrawal mesa-while i is p ieiable to use the same 1fiuidizing medium through the transverse. jets; it possible to operatethe regulation and control of the withdrawal of particles. by utilizingseparate gaseous streams'whlch have independent sources of supply.For-example, at the lower end of the withdrawal conduit '20 wherecontaminated catalyst particles are Withdrawn fromthe reaction zone,steam maybe supplied through jet 24. to pass upwardly into the standpipe20 and against the underside of the swinging ofincenter vane 2| while anair stream such as supplied to 25 and jet 23 may effect the eduction andtransfer of particles o through conduit 22. In this case, means may bprovided for nr r rtioning-the stream flows through each .01 the jetnozzles 23 and 24 in a manner that the two-way valve 2B proper? assaavstions flow. In other words, as gaseous flow is increased through jet 23the flow is decreased through jet 2t and conversely with the desire toincrease flow through jet 24, the flow. is de, creased thro'ughjet 23. x-i- It may again be noted, that it is not intended to limit the presentimproved and simplified operation which eliminates the slide v'a'lvetype of flow control of particles, to the Catalytic. cracking ofhydrocarbons in separate confined zones, for obviously, a similaroperation may'be applied to the conversion of other reactant streamswhich may in turn be effected advantageously within fluidized conversionzones; and in each case a suitable fluidizing or gaseous stream which isinert or useful in connection with the processing, is supplied to thecontrol jets at the lower end of each of the particle withdrawal 'c'on''duits from each of the separate confined conver sion zones. the samemanner as the'catalyst particles, for processes other than catalyticconversions, or al ternately, subdivided particles may be contacted ortreated in a fluidized operation and in separate zones transferring theparticles in the manner of the present invention. For example, thetreating and distillation of shale may be effected from finely groundshale particles being introduced to the reaction zone, together with hotash-like particles, the latter being introduced to the res action zonefrom'a heating zone in order to supply the desired heat fordistillation; and residual carbonaceous matter being burned fromdistilla-f tion residue in the regeneration-zone to effect the desiredheating of particles "for return to the reaction zone. M

I claim as my invention:

1. In a contacting process whereina stream of fluid is passed upwardlythrougha fluidized bed of subdivided solid'particles in a contactingInert particles may be transferred in zone and solidparticles'transferred from said zone to another zone, theimprovementwhich comprises continuously withdrawing subdivided particlesdownwardly from the fluidized bed in said contacting zone in arelatively dense phase fluidized column, discharging the withdrawnparticles into a transfer conduit disposed transversely with respect tosaid column and communicating with said other zone, maintaining at leasttwo jet streams in said conduit below said column, directing one of saidjet streams upwardly into said column in a manner hindering thedischarge of particles therefrom, and directing another of said jetstreams away from said column in the direction of said other zone.

2. The method of claim 1 further characterized in that a substantiallyconstant rate of gaseous flow is independently proportioned between saidjet streams whereby the increase in flow .to' one of said jets decreasesflow. through the accompanying jet.

3. In a fluidized contacting process wherein a hydrocarbon reactantstream contacts subdivided particles in a fluidized bed in a confinedreaction zone, a reactivating gaseous medium contacts a fluidized bed ofsubdivided particles within a confined regenerating zone, resultingconversion product streams are continuously withdrawn from each of thezones, and contacted particles are continuously passed from each zone tothe other to provide a continuous conversion process, the improvementwhich comprises, withdrawing contacted subdivided particlesdownwardly-from the fluidized bed in each of -said zones in a relativelydense phase descendingiand.conflnedrcolumn of particles, maintainingtransverse jet streams of air below the descending column of particlesfrom said reaction zone, with one of said streams directed upwardly intosaid descending column of particles and hindering particle flowtherefrom, directing the other of said transverse air streams away fromthe descending column of particles in a manner passing withdrawnparticlesto the lower end of said regenerating zone, proportioning aconstant volume of air between said transverse jet streams and.regulating pressure at the lower end of said column of particles and thewithdrawal and transfer of contaminated particles from said descendingcolumn of particles to said regenerating zone, maintaining transversejet streams of steam below the fluidized descending column of particlesfrom said regenerating zone, directing one of said streams of steamupwardly into said descending column of particles and hindering thewithdrawal of particles therefrom, directing the other of said jetstreams away from the lower end of said column .of particles andeffecting the passage of regenerated particles to said reaction zone,and proportioning the steam between last said jet streams and effectingthereby the regulation and control of the transfer of regeneratedparticles to said reaction zone.

4; The method of claim 3 further characterized in that the proportioningof the air streams and the transfer of subdivided solid particles to theregeneration. zone is varied in accordance with the fluidized bed levelmaintained within said reaction zone,.and the proportioning of the steamstreams regulating the withdrawal and transfer of regenerated catalyststo the reaction zone is varied in accordance with the temperaturemaintained within the fluidized bed of the reaction zone.

5. The method of claim 4 still further characterized in that internalpressure is measured within the upper portion of each of said contactingzones and the withdrawal of conversion product from one of said zones isregulated to maintain a substantially constant difierential pressurebetween said contacting zones.

6. Apparatus for effecting the fluidized contacting of subdividedparticles in a conversion process, comprising in combination, avertically disposed reaction chamber and a vertically disposedregenerating chamber, each of said chambers having fluid and particleinlet means, fluid outlet means from the upper portion thereof andparticle withdrawal means, each of the latter means having asubstantially. vertical conduit section connecting with particletransfer conduits, each transfer conduit extending from said verticalconduit sections to the other of said chambers, an off-center pivotedvane in the lower portion of each of said vertical outlet conduitsections, a fluid jet nozzle directed upwardly towards the vane in eachof the outlet conduit sections, another jet nozzle directed across thelower end of each of said sections transversely to the first saidnozzles and into said transfer conduits whereby particles passingdownwardly through each of the withdrawal outlet sections aretransferred to the other of said chambers, valve and conduit meansconnecting to each fluid jet nozzle at each withdrawal conduit section,said valve means proportioning fluid flow between said jet nozzles ineach withdrawal conduit and thereby controlling pressure below each ofsaid pivoted vanes and regulating flow of particles between chambers.

7. The apparatus of claim 6 further characterized in that said valvemeans connecting to the transversely positioned jet nozzles at each ofsaid withdrawal conduit sections is a twoway valve, said two-way valveconnecting to said transverse jet nozzles in a manner to proportion aconstant flow therebetween, whereby an increase in flow through a jetnozzle directed upwardly into a vertical conduit section effects adecrease in the flow through the accompanying transverse nozzle directedinto a transfer conduit, and conversely where flow is increased into a,jet nozzle directed into said transfer conduit then flow is decreasedthrough said accompanying nozzle directed upwardly into said verticalsection.

8. A contacting apparatus comprising a con-, tacting chamber, means formaintaining a fluidized bed of subdivided solid particles in said 10transfer conduit in the direction of said second chamber.

9. A contacting apparatus comprising a contacting chamber, means formaintaining a fluidized bed of subdivided solid particles in saidchamber, a downwardly extending standpipe communicating with the lowerportion of said chamber, a transfer conduit connected to the lower endof said standpipe and to a second contacting chamber, said conduit beingdisposed transversely with respect to the standpipe, an off-centerpivoted vane in the lower portion of the standpipe, and a pair of fluidjet nozzles in said conduit adjacent the lower end of the standpipe, oneof said nozzles being directed upwardly into the standpipe toward saidvane and the other being directed lengthwise of the transfer conduit inthe direction of said second chamber.

JON BEAM.

REFERENCES CITED 1 The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,416,729 Arveson Mar. 4, 1947

1. IN A CONTACTING PROCESS WHEREIN A STREAM OF FLUID IS PASSED UPWARDLYTHROUGH A FLUIDIZED BED OF SUBDIVIDED SOLID PARTICLES TRANSFERRED FROMSAID ZONE AND SOLID PARTICLES TRANSFERRED FROM SAID ZONE TO ANOTHERZONE, THE IMPROVEMENT WHICH COMPRISES CONTINUOUSLY WITHDRAWINGSUBDIVIDED PARTICLES DOWNWARDLY FROM THE FLUIDIZED BED IN SAIDCONTACTING ZONE IN A RELATIVELY DENSE PHASE FLUIDIZED COLUMN,DISCHARGING THE WITHDRAWN PARTICLES INTO A TRASFER CONDUIT DISPOSEDTRANSVERSELY WITH RESPECT TO SAID COLUMN AND COMMUNICATING WITH SAIDOTHER ZONE, MAINTAINING AT LEAST TWO JET STREAMS IN SAID CONDUIT BELOWSAID COLUMN, DIRECTING ONE OF SAID JET STREAMS UPWARDLY INTO SAID COLUMNIN A MANNER HINDERING THE DISCHARGE OF PARTICLES THEREFROM, ANDDIRECTIONS ANOTHER OF SAID JET STREAMS AWAY FROM SAID COLUMN IN THEDIRECTION OF SAID OTHER ZONE.